The invention relates to a skid-mounted natural gas liquefaction device, which is characterized by comprising a pre-cooling system skid, a cold box skid, a liquefaction system skid and an overcooling system skid, wherein the pre-cooling system skid is connected with the cold box skid through a pipeline; the cold box skid is connected with the liquefaction system skid and the overcooling system skid through a pipeline respectively, the pre-cooling system skid is formed by independently assembling equipment and a pipeline of a pre-cooling circulation system, the cold box skid is formed by independently assembling equipment and a pipeline of a natural gas liquefaction system, the liquefaction system skid is formed by independently assembling equipment and a pipeline of a liquefied gas expansion cooling system, the overcooling system skid is formed by independently assembling equipment and a pipeline of an overcooling air expansion cooling system, and then each independent skid is assembled into the whole set of skid-mounted device. Therefore, the skid-mounted device is convenient to transport and mount, and can be widely applied to natural gas liquefaction production processes of offshore and onshore small gas fields.